Over the last few decades, mammography and ultrasound have served as the main screening tools to detect breast cancer. With the increase in availability of magnetic resonance imaging (MRI), comparisons have been made between mammography, alone or in further combination with ultrasound, and MRI in the detection of breast cancer. It has been reported that MRI is twice as sensitive as, and three times more specific than, mammography (Kuhl et al., J. Clin. Oncol. 23: 8469-8476 (2005)). MRI is even more effective than mammography in combination with ultrasound in accurately defining the extent and type of disease (Kuhl et al. (2005), supra; and Berg et al., Radiology 233: 830-849 (2004)). Unfortunately, MRI is much more costly than mammography and ultrasound, even when mammography and ultrasound are used in combination, and the imaging procedures takes much longer. Therefore, the use of MRI is currently limited to patients at high risk for developing breast cancer.
Tomosynthesis (Suryanarayanan et al., Acad. Radiol. 7(12): 1085-1097 (2000)) and breast computed tomography (CT) (Boone et al., Radiology 221: 657-667 (2001)) are three-dimensional (3-D) imaging technologies currently under development. It is expected that at least one of these technologies will eventually replace digital mammography as the tool of choice in the screening and diagnosis of breast cancer. Although these technologies offer advantages over mammography, they also present some major disadvantages. For example, the breast CT, while it rotates a low kilo Volt (kV) x-ray source around the breast of a patient in the prone position and can image the ductal system of the breast and tumors, it cannot image the tissues of the breast close to the chest wall and any tumors that might occur there. Digital tomosynthesis mammography (DTM) involves generating two-dimensional projection-view images, which are reconstructed to provide three-dimensional structural information of the imaged portion of the breast; however, the two-dimensional projection-view images are generated from a limited number of angles over a limited angular range (Zhang et al., Med. Phys. 33(10): 3781-3795 (2006)). Given the limited projections, clear images can only be generated in a limited thickness of breast tissues. While DTM may be suitable for the set-up used for mammography, i.e., pressing the breast into a uniform thickness between two plastic plates, it cannot image the entire breast in its natural shape. It is the aforementioned disadvantages that render these technologies, in their current state, unsuitable for imaging of the breast for treatment of a tumor using surgery, radiation, or another targeted treatment modality. The inability to image tumors close to the chest wall and the inability to image the breast in its natural state make it difficult for a surgeon to rely on such images to determine accurately the location of a tumor for complete surgical removal and/or thorough treatment with radiation or another therapeutic agent. The inability to determine accurately the location of a tumor for surgical removal contributes to repeat lumpectomies, about 30% of which result in excised tissues containing malignant cells on their margins.
In view of the foregoing, it is an object of the present disclosure to provide a method and a system for using DTM translationally in the absence of pressing plates. This and other objects, as well as inventive features, will become apparent from the detailed description provided herein.